Ambient air pollutants, increased anaemia risk, and vulnerable subgroups: evidence from a large group of workers in South China.

Background: Previous epidemiological studies indicated a potential correlation between air pollution and anaemia, particularly in children, pregnant women, and the elderly. However, evidence is insufficient for workers exposed to air pollution while working in environments with other occupational hazards. Based on data from a substantial population of workers in southern China, we aimed to examine the relationships between different air pollutants and both haemoglobin (Hb) concentration and the prevalence of anaemia. Methods: In this cross-sectional analysis, we recruited 372 290 workers from the National Occupational Disease Surveillance Platform and utilised a mixed-effects model to explore the association of various air pollutants (including PM2.5, PM10, PMcoarse, O3, and NO2) with Hb concentration and the prevalence of anaemia. We ran stratified analyses by various demographic characteristics and occupational variabels. Results: Each 5 μg/m3 increase in the concentration of PM2.5, PM10, PMcoarse, O3, and NO2 corresponds to a 2.037 g/L (95% confidence interval (CI) = 1.938, 2.137), 1.096 g/L (95% CI = 1.040, 1.152), 1.412 g/L (95% CI = 1.313, 1.510), 0.518 g/L (95% CI = 0.489, 0.547), and 0.250 g/L (95% CI = 0.219, 0.281) decrease in Hb concentration, respectively. The prevalence of anaemia increased by 11.3% (95% CI = 7.3, 15.5), 5.0% (95% CI = 2.8, 7.3), and 4.5% (95% CI = 6, 8.5) for a 5 μg/m3 increase in PM2.5, PM10, and PMcoarse, respectively, with the impact being more pronounced in the non-benzene-exposed population. Subgroup analyses suggested potential variations in susceptibility to the same air pollutant across different demographics and occupational variables. Conclusions: The Hb levels among the workers in our sample were associated with various atmospheric pollutants, with certain demographic and occupational subgroups being particularly vulnerable. These results highlight the need for targeted air pollution control and occupational health interventions, particularly for vulnerable demographic and occupational subgroups.